Harvesting optimization with stochastic differential equations models: is the optimal enemy of the good?

We can describe the size evolution of a harvested population in a randomly varying environment using stochastic differential equations. Previously, we have compared the profit performance of four harvesting policies: (i) optimal variable effort policy, based on variable effort; (ii) optimal penalized variable effort policies, penalized versions based on including an artificial running energy cost on the effort; (iii) stepwise policies, staircase versions where the harvesting effort is determined at the beginning of each year (or of each biennium) and kept constant throughout that year (or biennium); (iv) constant harvesting effort sustainable policy, based on constant effort. They have different properties, so it is also worth looking at combinations of such policies and studying the single and cross-effects of the amount of penalization, the absence or presence and type of steps, and the restraints on minimum and maximum allowed efforts. Using data based on a real harvested population and considering a logistic growth model, we perform such a comparison study of pure and mixed policies in terms of profit, applicability, and other relevant properties. We end up answering the question: is the optimal enemy of the good?CEMAPRE/REM; FCT - Project UIDB/05069/2020; CIMA; FCT - Project UID/04674/202

Fisheries management in random environments: Comparison of harvesting policies for the logistic model

We describe the growth dynamics of a harvested fish population in a random environment using a stochastic differential equation logistic model, where the harvest term depends on a constant or a variable fishing effort. We consider revenues to be proportional to the yield and costs to be quadratic in terms of effort. We compare the optimal expected profit obtained with two types of harvesting policies, one based on variable effort, which is inapplicable, and the other based on a constant effort, which is applicable and sustainable. We answer two new questions: (a) What is the constant effort that optimizes the expected profit per unit time? (b) How do the two policies compare in terms of performance? We show that, in a realistic situation, there is only a slight reduction in profit when choosing the applicable constant effort policy instead of the inapplicable policy with variable effort

Anaphylaxis in Pregnancy: a Rare Cause of Neonatal Mortality

Anaphylaxis is a rare condition in pregnancy. Drugs are the aetiological agents most often implicated. Maternal anaphylaxis can lead to significant fetal morbidity and even mortality if uterine perfusion and maternal oxygenation are compromised. Significant risk of neonatal neurological damage or death can occur even when the maternal clinical outcome is favourable. The authors present the case of a newborn, born at gestational age of 29 weeks, who died at 11 days of life with hypoxic-ischaemic cerebral injuries as a consequence of maternal anaphylaxis following the administration of amoxicillin in the community setting.info:eu-repo/semantics/publishedVersio

Dscam1 in pancrustacean immunity: current status and a look to the future

The Down syndrome cell adhesion molecule 1 (Dscam1) gene is an extraordinary example of diversity: by combining alternatively spliced exons, thousands of isoforms can be produced from just one gene. So far, such diversity in this gene has only been found in insects and crustaceans, and its essential part in neural wiring has been well-characterized for Drosophila melanogaster. Ten years ago evidence from D. melanogaster showed that the Dscam1 gene is involved in insect immune defense and work on Anopheles gambiae indicated that it is a hypervariable immune receptor. These exciting findings showed that via processes of somatic diversification insects have the possibility to produce unexpected immune molecule diversity, and it was hypothesized that Dscam1 could provide the mechanistic underpinnings of specific immune responses. Since these first publications the quest to understand the function of this gene has uncovered fascinating insights from insects and crustaceans. However, we are still far from a complete understanding of how Dscam1 functions in relation to parasites and pathogens and its full relevance for the immune system. In this Hypothesis and Theory article, we first briefly introduce Dscam1 and what we know so far about how it might function in immunity. By focusing on seven questions, we then share our sometimes contrasting thoughts on what the evidence tells us so far, what essential experiments remain to be done, and the future prospects, with the aim to provide a multiangled view on what this fascinating gene has to do with immune defense

Cobertura da sala do relicário no Mosteiro de Santa Cruz: notas sobre a intervenção

A alvenaria e a madeira são materiais de construção tradicionais, que surgem actualmente com interesse renovado na indústria de construção. No caso da madeira, e de um modo geral, muitos sistemas estruturais continuam a desempenhar as suas funções (embora muitos deles tenham sido substituídos por lajes aligeiradas em betão armado no decurso do século XX), o que requer frequentemente inspecções para averiguar a segurança estrutural, bem como trabalhos de conservação e reabilitação. É apresentado neste artigo um caso de estudo relativo à cobertura da Sala do Relicário no Mosteiro de Santa Cruz, em Coimbra. Trata-se de uma situação onde existiam diversas anomalias, intervenções sucessivas no passado e uma configuração estrutural particularmente complexa. Depois de analisadas as diferentes possibilidades de intervenção, decidiu-se em conjunto com o dono de obra (IPPAR, Direcção Regional de Coimbra), substituir a cobertura existente por uma cobertura nova, recorrendo a madeira maciça. Pela dimensão das peças e pela complexidade da estrutura, entende-se que esta obra é única no contexto nacional, tendo sido possível verificar que a utilização de técnicas e processos construtivos tradicionais constitui uma opção válida no projecto corrente

VO2 prediction based on physiologic and mechanical exercise measurements

The Cardiopulmonary Exercise Test (CPET) is a diagnostic test that evaluates the functional capacity of an individual through the integrated response of the cardiovascular, respiratory, and metabolic systems. VO2 max is the parameter that access functional capacity, although it’s difficult to achieve given the effort that implies. In recent years, an increase in computing capabilities combined with the available storage of large amounts of information has led to a heightened interest in machine learning (ML). We aimed in this study to enable CPET with ML models that allow predicting oxygen consumption in healthy individuals. The study methodology is based on the cleaning and exploratory analysis of a public database with about 992 CPETs performed on healthy individuals and athletes. To predict each value of VO2 (~569,000 instances), five ML algorithms were used (Random Forests, kNN, Neural Networks, Linear Regression, and SVM) with heart rate, respiratory rate, time from the beginning of the exam and treadmill speed, using a 20-fold cross-validation. The best result came from the Random Forest model, with a R2 of 0.88 and a RMSE of 334.34 ml.min-1. Furthermore, using the same methodology but different features, we tried to predict the VO2max with the 724 adult participants with a maximal test (RER≥1.05) but weaker results were obtained (the best model was the Linear Regression, with a R2 of 0.50 and a RMSE of 498.06 ml.min-1). Still, this model showed a better correlation with the real VO2max than the Wasserman equation (R=0.71 vs R=0.59). It is possible to predict with accuracy breath-by-breath VO2, based on easy-to-obtain physiological and mechanical measurements.info:eu-repo/semantics/publishedVersio

Nicolau Livedoid Dermatitis following intramuscular benzathine penicillin injection

We report the case of a 64-year-old male presenting with a rapidly enlarging painful violaceous plaque in the left buttock and posterior thigh, following a gluteal intramuscular injection of benzathine penicillin. Associated urinary incontinence and lower left limb paresis were consistent with sciatic and lower sacral nerve damage, as confirmed by electromyography. Additional underlying muscular damage was observed in ultrasound and computer tomodensitometry scans and supported by high serum levels of creatine kinase and lactate dehydrogenase. Aggressive treatment was performed with fluid expansion, intravenous steroid bolus, vasodilators and anticoagulation, resulting in slow improvement of cutaneous and muscular lesions. However, no significant effect was observed on neurologic dysfunction after 6 months of regular neuromuscular rehabilitation. Nicolau Livedoid Dermatitis is a rare and potentially fatal condition showing variable levels of tissue impairment and unpredictable course and prognosis. Specific treatment is not consensual and the efficacy of any particular treatment remains to be established